In applications having light projection, one technique to allow mechanical motion to direct the light in the x and y axis is to use two discrete mirrors with one mirror allowing for rotation of the image in the x axis which is further superimposed on another mirror allowing for further rotation in the y axis. An advantage of this system is simplicity—the two axes can be parked on a rotating shaft such as a motor or a galvanometer with a simple control mechanism to control the position of the mirrors. A principal problem with this type of control system is that the reflection occurs on two surfaces resulting in losses and inaccuracies from the mirror surfaces imperfections. These issues result in a reduction of image intensity and quality. The two mirror configuration also requires a larger size/footprint. The primary mirror may be small but the secondary mirror, which collects all the diverging light from the primary source will need to be larger.
In addition, various methods exist for tip and tilting, x and y translation, of a single reflective surface. Some of them are used in sensitive applications such as in the aviation, space and medical fields and are very accurate, sometimes down to the milliradian. They use forces such as magnetic, mechanical, piezo, and other means of locomotion to tilt a system that is held in either a gimbal or a ball joint. Such systems need complex and carefully manufactured electronics to close a feedback loop allowing for proper functioning of the system rendering and tilt systems with a single reflective surface has a limited range of motion despite the higher resolution and cost, further limiting their applicability to most general applications. Alternately, other existing techniques that have a single reflective surface and employ a mechanical system need articulated arms and carefully designed ball joints to function, similarly saddling them with higher manufacturing costs and requiring larger footprints for deployment.
Another technique of enabling a single reflective surface in more than one axis of rotation employs a primary rotation medium that is coupled to a secondary rotation medium which in turn rotates the mirror. These devices actually move the second motor and as a result need more space for operation, again increasing the footprint of the system. The addition of a moving second motor adds mass to the moving components and increases inertia. The inertia of the motor can prohibit a smaller, lower power first motor from being used or from a small first motor to move with higher acceleration and deceleration. This higher inertia also renders such systems more prone to errors due to the larger moving masses. Further because the mirror is far from the main axis of rotation, the mirror surface has to be larger, making it impractical for limited physical space applications. These factors contribute to making these systems less accurate and requiring more space in a footprint for deployment in any control system.
Thus, there exists a need for a device and a method that provides tip and tilt control on two axis, offers the ability for systems to calculate the relative or absolute position of the mount surface or element quickly and efficiently, provide for fixed motors which in turn lower motor torque and provide a lower inertia of moving components and be cost effective. The system also needs to provide the motion at high speed, have a small form factor /net volume, use smaller motors to save weight, reduce cost, reduce inertial interference, lower power consumption, and result in robust, compact, cost effective device with high accuracy for mechanical and electrical systems.